This is a fun little game! Reminds me of those troll games like I Wanna Be The Guy or CatMario, and I like that very much. It's very impressive, considering it's your first game, where the game has surprisingly smooth movement and few issues. The only issue I've encountered was the spike that falls on you never respawned once triggered. I really see potential in you, and I am looking forward to what you'll be able to achieve in the future!
For some recommendations, I'd say you should make both the tileset and the background look a bit better. Currently, it's the default Unity blue, but something simple as the background seen on the game's thumbnail would definitely elevate the game a lot. Also, consider learning about parallaxing background, which is a cool yet easy way to make excellent backgrounds. You should also try to provide a story to the game, something as simple as a slide, or complex stuff like environmental storytelling would do.
Anyway, I hope you are having fun making this game and keep on making games! Keep up the good work!